Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * include/linux/idr.h |
| 3 | * |
| 4 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
| 5 | * Copyright (C) 2002 by Concurrent Computer Corporation |
| 6 | * Distributed under the GNU GPL license version 2. |
| 7 | * |
| 8 | * Small id to pointer translation service avoiding fixed sized |
| 9 | * tables. |
| 10 | */ |
Luben Tuikov | f668ab1 | 2005-11-08 17:14:08 +0100 | [diff] [blame] | 11 | |
| 12 | #ifndef __IDR_H__ |
| 13 | #define __IDR_H__ |
| 14 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/types.h> |
| 16 | #include <linux/bitops.h> |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 17 | #include <linux/init.h> |
Nadia Derbey | 2027d1a | 2008-07-25 01:47:57 -0700 | [diff] [blame] | 18 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | |
| 20 | #if BITS_PER_LONG == 32 |
| 21 | # define IDR_BITS 5 |
| 22 | # define IDR_FULL 0xfffffffful |
| 23 | /* We can only use two of the bits in the top level because there is |
| 24 | only one possible bit in the top level (5 bits * 7 levels = 35 |
| 25 | bits, but you only use 31 bits in the id). */ |
| 26 | # define TOP_LEVEL_FULL (IDR_FULL >> 30) |
| 27 | #elif BITS_PER_LONG == 64 |
| 28 | # define IDR_BITS 6 |
| 29 | # define IDR_FULL 0xfffffffffffffffful |
| 30 | /* We can only use two of the bits in the top level because there is |
| 31 | only one possible bit in the top level (6 bits * 6 levels = 36 |
| 32 | bits, but you only use 31 bits in the id). */ |
| 33 | # define TOP_LEVEL_FULL (IDR_FULL >> 62) |
| 34 | #else |
| 35 | # error "BITS_PER_LONG is not 32 or 64" |
| 36 | #endif |
| 37 | |
| 38 | #define IDR_SIZE (1 << IDR_BITS) |
| 39 | #define IDR_MASK ((1 << IDR_BITS)-1) |
| 40 | |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 41 | #define MAX_IDR_SHIFT (sizeof(int)*8 - 1) |
| 42 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
| 43 | #define MAX_IDR_MASK (MAX_IDR_BIT - 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | |
| 45 | /* Leave the possibility of an incomplete final layer */ |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 46 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | /* Number of id_layer structs to leave in free list */ |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 49 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | |
| 51 | struct idr_layer { |
| 52 | unsigned long bitmap; /* A zero bit means "space here" */ |
Arnd Bergmann | d2c2486 | 2010-02-26 14:53:26 +0100 | [diff] [blame] | 53 | struct idr_layer __rcu *ary[1<<IDR_BITS]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | int count; /* When zero, we can release it */ |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 55 | int layer; /* distance from leaf */ |
Nadia Derbey | 2027d1a | 2008-07-25 01:47:57 -0700 | [diff] [blame] | 56 | struct rcu_head rcu_head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | }; |
| 58 | |
| 59 | struct idr { |
Arnd Bergmann | d2c2486 | 2010-02-26 14:53:26 +0100 | [diff] [blame] | 60 | struct idr_layer __rcu *top; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | struct idr_layer *id_free; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 62 | int layers; /* only valid without concurrent changes */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | int id_free_cnt; |
| 64 | spinlock_t lock; |
| 65 | }; |
| 66 | |
| 67 | #define IDR_INIT(name) \ |
| 68 | { \ |
| 69 | .top = NULL, \ |
| 70 | .id_free = NULL, \ |
| 71 | .layers = 0, \ |
| 72 | .id_free_cnt = 0, \ |
Ingo Molnar | e4d9191 | 2006-07-03 00:24:34 -0700 | [diff] [blame] | 73 | .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | } |
| 75 | #define DEFINE_IDR(name) struct idr name = IDR_INIT(name) |
| 76 | |
Nadia Derbey | 944ca05 | 2008-07-25 01:47:59 -0700 | [diff] [blame] | 77 | /* Actions to be taken after a call to _idr_sub_alloc */ |
| 78 | #define IDR_NEED_TO_GROW -2 |
| 79 | #define IDR_NOMORE_SPACE -3 |
| 80 | |
| 81 | #define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC) |
| 82 | |
Nadia Derbey | f9c46d6 | 2008-07-25 01:48:01 -0700 | [diff] [blame] | 83 | /** |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 84 | * DOC: idr sync |
Nadia Derbey | f9c46d6 | 2008-07-25 01:48:01 -0700 | [diff] [blame] | 85 | * idr synchronization (stolen from radix-tree.h) |
| 86 | * |
| 87 | * idr_find() is able to be called locklessly, using RCU. The caller must |
| 88 | * ensure calls to this function are made within rcu_read_lock() regions. |
| 89 | * Other readers (lock-free or otherwise) and modifications may be running |
| 90 | * concurrently. |
| 91 | * |
| 92 | * It is still required that the caller manage the synchronization and |
| 93 | * lifetimes of the items. So if RCU lock-free lookups are used, typically |
| 94 | * this would mean that the items have their own locks, or are amenable to |
| 95 | * lock-free access; and that the items are freed by RCU (or only freed after |
| 96 | * having been deleted from the idr tree *and* a synchronize_rcu() grace |
| 97 | * period). |
| 98 | */ |
| 99 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | /* |
| 101 | * This is what we export. |
| 102 | */ |
| 103 | |
| 104 | void *idr_find(struct idr *idp, int id); |
Al Viro | fd4f2df | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 105 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | int idr_get_new(struct idr *idp, void *ptr, int *id); |
| 107 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id); |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 108 | int idr_for_each(struct idr *idp, |
| 109 | int (*fn)(int id, void *p, void *data), void *data); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 110 | void *idr_get_next(struct idr *idp, int *nextid); |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 111 | void *idr_replace(struct idr *idp, void *ptr, int id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | void idr_remove(struct idr *idp, int id); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 113 | void idr_remove_all(struct idr *idp); |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 114 | void idr_destroy(struct idr *idp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | void idr_init(struct idr *idp); |
Luben Tuikov | f668ab1 | 2005-11-08 17:14:08 +0100 | [diff] [blame] | 116 | |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 117 | |
| 118 | /* |
| 119 | * IDA - IDR based id allocator, use when translation from id to |
| 120 | * pointer isn't necessary. |
Namhyung Kim | ed9f524 | 2010-09-16 01:30:19 +0900 | [diff] [blame] | 121 | * |
| 122 | * IDA_BITMAP_LONGS is calculated to be one less to accommodate |
| 123 | * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 124 | */ |
| 125 | #define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */ |
Namhyung Kim | ed9f524 | 2010-09-16 01:30:19 +0900 | [diff] [blame] | 126 | #define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long) - 1) |
| 127 | #define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 128 | |
| 129 | struct ida_bitmap { |
| 130 | long nr_busy; |
| 131 | unsigned long bitmap[IDA_BITMAP_LONGS]; |
| 132 | }; |
| 133 | |
| 134 | struct ida { |
| 135 | struct idr idr; |
| 136 | struct ida_bitmap *free_bitmap; |
| 137 | }; |
| 138 | |
| 139 | #define IDA_INIT(name) { .idr = IDR_INIT(name), .free_bitmap = NULL, } |
| 140 | #define DEFINE_IDA(name) struct ida name = IDA_INIT(name) |
| 141 | |
| 142 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask); |
| 143 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id); |
| 144 | int ida_get_new(struct ida *ida, int *p_id); |
| 145 | void ida_remove(struct ida *ida, int id); |
| 146 | void ida_destroy(struct ida *ida); |
| 147 | void ida_init(struct ida *ida); |
| 148 | |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 149 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
| 150 | gfp_t gfp_mask); |
| 151 | void ida_simple_remove(struct ida *ida, unsigned int id); |
| 152 | |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 153 | void __init idr_init_cache(void); |
| 154 | |
Philipp Reisner | 9749f30 | 2011-07-20 14:59:37 +0200 | [diff] [blame] | 155 | /** |
| 156 | * idr_for_each_entry - iterate over an idr's elements of a given type |
| 157 | * @idp: idr handle |
| 158 | * @entry: the type * to use as cursor |
| 159 | * @id: id entry's key |
| 160 | */ |
| 161 | #define idr_for_each_entry(idp, entry, id) \ |
| 162 | for (id = 0, entry = (typeof(entry))idr_get_next((idp), &(id)); \ |
| 163 | entry != NULL; \ |
| 164 | ++id, entry = (typeof(entry))idr_get_next((idp), &(id))) |
| 165 | |
Luben Tuikov | f668ab1 | 2005-11-08 17:14:08 +0100 | [diff] [blame] | 166 | #endif /* __IDR_H__ */ |